import type { Range, Variables } from "./types";

export interface FunctionPreset {
  name: string;
  expression: string;
  // The view it opens with (with one variable, y fits the curve), and where the runs start
  x: Range;
  y?: Range;
  start: number[];
}

export const PRESETS: Record<Variables, FunctionPreset[]> = {
  1: [
    { name: "Quadratic", expression: "x^2", x: [-1.5, 1.5], start: [1] },
    { name: "Local minima", expression: "x^2 - 0.1cos(20x)", x: [-1.5, 1.5], start: [1] },
    { name: "Plateau", expression: "x^4", x: [-1.5, 1.5], start: [1] },
  ],
  2: [
    { name: "Quadratic bowl", expression: "x^2 + 3y^2", x: [-1.5, 1.5], y: [-1.5, 1.5], start: [1, 1] },
    { name: "Small", expression: "(0.05x)^2 + 3(0.05y)^2", x: [-1.5, 1.5], y: [-1.5, 1.5], start: [1, 1] },
    { name: "Ackley", expression: "-20exp(-0.2 sqrt(0.5(x^2 + y^2))) - exp(0.5(cos(2 pi x) + cos(2 pi y))) + e + 20", x: [-4, 4], y: [-4, 4], start: [2.6, 1.7] },
    { name: "Rastrigin", expression: "20 + (x^2 - 10cos(2 pi x)) + (y^2 - 10cos(2 pi y))", x: [-5.12, 5.12], y: [-5.12, 5.12], start: [3.2, 2.1] },
    { name: "Rosenbrock", expression: "(1 - x)^2 + 100(y - x^2)^2", x: [-2, 2], y: [-1, 3], start: [-1.5, 2] },
  ],
};

export const ALL_PRESETS = [...PRESETS[1], ...PRESETS[2]];

export const CUSTOM = "Custom";

// The function names logic.py allows (ALLOWED_NAMES); none of them contain a y
const FUNCTION_NAMES = /asin|acos|atan|sin|cos|tan|sqrt|abs|exp|log|ln|pi/g;

// 2 if the function uses y, else 1. Letters side by side multiply ("xy" is
// x·y), so any y left once the function names are removed counts.
export function detectVariables(expression: string): Variables {
  return /y/.test(expression.replace(FUNCTION_NAMES, "")) ? 2 : 1;
}